The present invention relates to the use of 4-chloro-5-[(4,5-dihydro-1H-imidazol-2-yl)-amino]-6-methoxy-2-methylpyrimi dine (=moxonidine) and the physiologically compatible acid addition salts thereof for the treatment and/or prophylaxis of functional gastrointestinal disturbances and illnesses in the region of the lower intestinal tracts, in particular for the treatment and/or prophylaxis of abdominal visceral pain which accompanies them, and to the preparation of medicaments suitable for this treatment and/or prophylaxis.